Piloted valves are often used to control the flow of fluids, in particular under increased fluid pressure. The pilot valve is a directly controlled valve, e.g. a solenoid valve or the like. By operating the pilot valve the pressure differences between the pilot chamber and the inlet/outlet can be changed to indirectly open the main valve. Under high fluid pressures this solution is more reliable and energy saving then having to overcome the pressure forces with a directly operated valve.
A valve of the above mentioned kind is for example known from WO 2014/207683 A1. Therein the diaphragm is supported by a washer ring and two ring disk-shaped support members. The center of the diaphragm is sandwiched between the two ring disk-shaped support members. A radially outer end of the diaphragm is fixed to the housing by the washer ring. The pilot valve orifice is arranged in the center of both ring disk-shaped support members.
This solution works well to keep the diaphragm in place and the priority valve seat centered if the diaphragm is sufficiently rigid and does not expand or contract too much due to thermal influences or due to absorption of a refrigerant or other fluids. Consequently, the choice of materials for the diaphragm is rather limited. At the same time, the limited choice of materials also result in a limitation of the applications of the valve since the possible materials for the diaphragm are in some cases incompatible to certain fluids and/or pressure or temperature conditions.